Ventricular arrhythmia during Valsalva maneuver applied to facilitate resection of fourth ventricular neurocysticercosis cyst.

Sir,

An 8-year 32 kg American Society of Anesthesiologist (ASA) grade 1 female presented to us with headache for 8-9 months and was diagnosed to have a neurocysticercosis cyst (NCC) in fourth ventricle [Figure 1]. She did not have any history of cardio-respiratory abnormality, her routine investigations were normal and excepting occasional analgesics she was not on any medications. Patient underwent resection of the NCC under propofol, fentanyl, rocuronium and sevoflurane anesthesia in the prone position. She had stable intra-operative course until the commencement of dissection near fourth ventricle. As the NCC was not easily accessible we briefly applied Valsalva maneuver (VM) in order to facilitate its resection. However, immediately after the VM we observed ventricular premature contractions (VPCs). The arterial blood gas analysis of the patient was normal and there were no signs of inadequate depth of anesthesia or hypoxemia. As the VPCs were infrequent and were without any hemodynamic instability, we did not treat the VPCs and they resolved after few minutes. The surgical access to the cyst was still difficult and we re-applied the VM after 10 min, which resulted in ventricular bigeminy (VB) [Figure 2] and hypotension (invasive blood pressure of 87/40 mmHg) in our patient. We immediately terminated the VM, but the VB and hypotension persisted for which injection 2% lignocaine (1.5 mg/kg) and injection phenylephrine (50 μg) IV were administered. With those pharmacological interventions the VB and hypotension resolved. We did not reapply the VM further during the surgery and the rest of the surgery was uneventful. We obtained permission from patient's parent for this case report.

Figure 1

Magnetic resonance imaging showing fourth ventricular neurocysticercosis

Figure 2

The electrocardiography of the patients showing ventricular bigeminy

VM can cause transient increase intra-cranial pressure (ICP) and is sometimes employed during neurosurgery to facilitate the trans-sphenoidal resection of pituitary tumors, to confirm venous hemostasis and to facilitate resection of fourth ventricle NCC.[1] VB is a cardiac arrhythmia characterized by the occurrence of a normal heart beat followed by VPCs. Conditions such as coronary artery insufficiency, myocardial infarction, digitalis toxicity, hypokalemia, hypoxemia inadequate analgesia, old age and halothane use can lead to VB.[23] However, our patient did not have any risk factors for VB. Sudden onset VB has an increased potential for ventricular fibrillation and lignocaine (1.5 mg/kg followed by 1-4 mg/min if needed) IV is the treatment of choice for VB, which is unresponsive to correction of its initiating event.[2]

The trigeminocardiac reflex (TCR) is a sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve.[4] VB has been reported as a manifestation of occulo cardiac reflex, which is a variant of TCR.[45] The afferent pathway of TCR continues to the main sensory nucleus of the trigeminal nerve under the floor of the fourth ventricle.[4] In our case the VB might have resulted from TCR due to stimulation of trigeminal nucleus by an increase in the ICP (due to VM) in the vicinity of the trigeminal nerve nucleus. Hence, VM might be helpful in some supratentorial surgeries, but it can lead to VB especially if applied in cases of posterior fossa surgery.